Advances in magnetic resonance imaging for the assessment of paediatric focal epilepsy: a narrative review

Abstract

Background and objective: Epilepsy affects approximately 50 million people worldwide, with 30-40% of patients not responding to medication, necessitating alternative therapies such as surgical intervention. However, the accurate localization of epileptogenic lesions, particularly in pediatric magnetic resonance imaging (MRI)-negative drug-resistant epilepsy, remains a challenge. This paper reviews advanced neuroimaging techniques aimed at improving the detection of such lesions to enhance surgical outcomes.

Methods: A comprehensive literature search was conducted using PubMed, focusing on advanced MRI sequences, focal epilepsy, and the integration of artificial intelligence (AI) in the diagnostic process.

Key content and findings: New MRI sequences, including magnetization prepared 2 rapid gradient echo (MP2RAGE), edge-enhancing gradient echo (EDGE), and fluid and white matter suppression (FLAWS), have demonstrated enhanced capabilities in detecting subtle epileptogenic lesions. Quantitative MRI techniques, notably magnetic resonance fingerprinting (MRF), alongside innovative post-processing methods, are emphasized for their effectiveness in delineating cortical malformations, whether used alone or in combination with ultra-high field MRI systems. Furthermore, the integration of AI in radiology is progressing, providing significant support in accurately localizing lesions, and potentially optimizing pre-surgical planning.

Conclusions: While advanced neuroimaging and AI offer significant improvements in the diagnostic process for epilepsy, some challenges remain. These include long acquisition times, the need for extensive data analysis, and a lack of large, standardized datasets for AI validation. However, the future holds promise as research continues to integrate these technologies into clinical practice. These efforts will improve the clinical applicability and effectiveness of these advanced techniques in epilepsy management, paving the way for more accurate diagnoses and better patient outcomes.

Keywords: Focal epilepsy; artificial intelligence (AI); malformations of cortical development (MCDs); neuroimaging; paediatric.

Figure 1

Comparative MRI sequences of MPRAGE (left) versus MP2RAGE (right) in an 8-year-old patient, highlighting a small left frontal FCD (arrows) with notably improved contrast on the MP2RAGE image. The focal cortical dysplasia shows increased cortical thickness and blurring at the grey-white matter junction. MRI, magnetic resonance imaging; MPRAGE, magnetization-prepared rapid gradient echo; MP2RAGE, magnetization prepared 2 rapid gradient echo; FCD, focal cortical dysplasia.

Figure 2

MP2RAGE post-processing techniques—edge enhanced (left) and edge only (right)—reveal marked contrast differentiation between grey and white matter regions. Arrows highlight the FCD (same patient as Figure 1). MP2RAGE, magnetization prepared 2 rapid gradient echo; FCD, focal cortical dysplasia.

Figure 3

Left FCD (blue arrow) depicted on FLAIR (left) and ASL (right) which shows a reduction in cerebral blood flow (orange arrow) compared to the surrounding cortex (same patient as Figures 1,2). FCD, focal cortical dysplasia; FLAIR, fluid attenuated inversion recovery; ASL, arterial spin labeling.

Figure 4

Language functional magnetic resonance imaging (fMRI) demonstrating bilateral frontal activation observed in a 10-year-old patient with prominent left-sided polymicrogyria (blue short arrows) during active verb generation tasks.

Figure 5

A 7-year-old patient with suspected cortical malformation area suggested by MELD classifier (left), compared with FLAIR (right) where the arrow points to the analogous region. The malformation of cortical development shows increased cortical thickness and blurring at the grey-white matter junction. MELD, Multi-centre Epilepsy Lesion Detection; FLAIR, fluid attenuated inversion recovery.